Multilevel Precedence and Preemption (MLPP) designates a priority scheme generally employed in military communication networks that assigns one of several precedence levels to specific calls or messages so that the system handles them in a predetermined order and time frame. MLPP can be used for gaining controlled access to network resources in which calls and messages can be preempted only by higher priority calls and messages. As a general principle, MLPP protocols are recognized only within a predefined domain, and the precedence level of a call outside the predefined domain is usually not recognized, but may continue to be transported transparently.
As noted, MLPP allows users on a special, private network the ability to signal explicitly the priority of a call as it is being set up. MLPP callers normally use a special telephone that includes an extra column of four buttons on the right side to allow the user to signal the priority for the call being placed. Since these are special telephones, their availability is limited and effort is required to install, move, and remove such telephones. While it is possible for a knowledgeable user to enter a series of special code sequences from a standard telephone keypad to activate the priority features, many users are infrequent users and only use the MLPP capability during an emergency. Consequently, users cannot generally recall the necessary codes, especially when lack of recent use is considered in light of the stress of a current emergency.
Thus, a need exists for a system that provides enhanced MLPP features without the need for a physical MLPP telephone instrument.